Paeoniflorin ameliorates ischemic neuronal damage in vitro via adenosine A1 receptor-mediated transactivation of epidermal growth factor receptor

GPCR-mediated natural products and compounds: Potential therapeutic targets for the treatment of neurological diseases

G protein-coupled receptors (GPCRs), widely expressed in the human central nervous system (CNS), perform numerous physiological functions and play a significant role in the pathogenesis of diseases. Consequently, identifying key therapeutic GPCRs targets for CNS-related diseases is garnering immense interest in research labs and pharmaceutical companies. However, using GPCRs drugs for treating neurodegenerative diseases has limitations, including side effects and uncertain effective time frame. Recognizing the rich history of herbal treatments for neurological disorders like stroke, Alzheimer's disease (AD), and Parkinson's disease (PD), modern pharmacological research is now focusing on the understanding of the efficacy of traditional Chinese medicinal herbs and compounds in modulating GPCRs and treatment of neurodegenerative conditions. This paper will offer a comprehensive, critical review of how certain natural products and compounds target GPCRs to treat neurological diseases. Conducting an in-depth study of herbal remedies and their efficacies against CNS-related disorders through GPCRs targeting will augment our strategies for treating neurological disorders. This will not only broaden our understanding of effective therapeutic methodologies but also identify the root causes of altered GPCRs signaling in the context of pathophysiological mechanisms in neurological diseases. Moreover, it would be informative for the creation of safer and more effective GPCR-mediated drugs, thereby establishing a foundation for future treatment of various neurological diseases.

Screening of potential antioxidant bioactive Q-markers of paeoniae radix rubra based on an integrated multimodal strategy

Background

Paeoniae Radix Rubra (PRR) has been used widely to promote blood circulation and eliminate blood stasis in China clinical practice owing to its extensive pharmacological effects. However, the "quality markers" (Q-markers) of the antioxidant effects remains unknown.

Object

To explore the Q-markers of antioxidant activity based on multiple strategies, which would provide reference for the quality evaluation of PRR based on specific pharmacodynamic-oriented.

Methods

Firstly, the "fingerprint" profiles of 15 batches of PRR were acquired and identified by ultrahigh performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF MS/MS) and the common peaks extracted. Meanwhile, the MTT assay was used to evaluate the effect of 15 batches of PRR on H2O2-induced oxidative stress in HT-22 cells. The antioxidant activity of PRR was investigated simultaneously by superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) commercial kits. The relationship between common peaks and antioxidant indexes were constructed by grey relational analysis (GRA) and partial least squares-discriminant analysis (PLS-DA) for the identification of preselected Q-markers. Secondly, experimental verification was conducted to investigate the protective effect of the preliminary components on HT-22 cells undergoing oxidative stress. Finally, for the further validation of effectiveness of antioxidant Q-markers, network pharmacology was applied to explore potential targets, and the molecular docking technology was used to value the binding ability of the potential active components of PRR to the antioxidant targets.

Results

Thirty-seven common peaks from 15 batches of PRR were identified qualitatively by UHPLC-Q-TOF MS/MS. The MTT assay showed that PRR could reduce the oxidative damage induced by H2O2 upon HT-22 cells according to the index of MDA, SOD and GSH. Eight potential antioxidant components were screened by spectrum-effect correlation analysis: paeoniflorin, galloylpaeoniflorin, albiflorin, 1,2,3,4,6-o-pentagalloylglucose, benzoylpaeoniflorin, pinocembrin, oleanic acid, and isorhamnetin-3-o-nehesperidine. Each of these preliminary components showed significant protections on cellular oxidative stress (P < 0.05). Interleukin-6 (IL-6), protein kinase B (AKT1), and tumor necrosis factor (TNF) were predicted to be the major potential targets of PRR, and the good binding ability were presented between the potential active components of PRR and each target as a whole.

Conclusion

Eight components were identified as the antioxidant Q-markers of PRR based on an integrated multimodal strategy.

Protective effects of a natural product, paeoniflorin, on ischemia reperfusion injury on rat ovary tissue: histopathological, immunohistochemical, and biochemical study

In this study, the main hypothesis is that paeoniflorin may inhibit some cellular processes such as oxidative stress and inflammation. For this reason, we aimed to investigate the potential protective effects of a natural compound, paeoniflorin, on rat model of ovarian ischemia-reperfusion injury by detecting the oxidative stress parameters and inflammatory process parameters. 42 female Wistar-albino rats were divided into 6 random groups. The rats were subjected to 3-hour ischemia and 3-hour reperfusion process. Then, paeoniflorin at doses of 25, 50 and 100 mg/kg were applied 30 min before the reperfusion. The levels of pro-inflammatory (IL-1-β, IL-6, TNF-α) and anti-inflammatory (IL-10, TGF-β) cytokines were measured by ELISA. Similarly, IL-6, IL-10, TNF-α, NF-κB p65) positivity rates were detected by immunohistochemical staining. Additionally, oxidative stress parameters (MDA, GSH, SOD) were measured by tissue biochemistry. Ischemia-reperfusion injury caused significant increase in the levels of SOD, MDA, TNF-α, IL-1-β, IL-6 and NF-κB p65, while paeoniflorin treatments improved the related parameters in a dose-dependent manner. As a conclusion, our findings support the evidence that paeoniflorin has a potential protective effects on ovarian ischemia-reperfusion injury. Further detailed studies should be performed to shed light the molecular mechanism of these protective effects.

Transactivation of receptor tyrosine kinases by purinergic P2Y and adenosine receptors

Transactivation of receptor tyrosine kinases (RTK) is a crosstalk mechanism exhibited by G-protein-coupled receptors (GPCR) to activate signaling pathways classically associated with growth factors. The discovery of RTK transactivation was a breakthrough in signal transduction that contributed to developing current concepts in intracellular signaling. RTK transactivation links GPCR signaling to important cellular processes, such as cell proliferation and differentiation, and explains the functional diversity of these receptors. Purinergic (P2Y and adenosine) receptors belong to class A of GPCR; in the present work, we systematically review the experimental evidence showing that purinergic receptors have the ability to transactivate RTK in multiple tissues and physiopathological conditions resulting in the modulation of cellular physiology. Of particular relevance, the crosstalk between purinergic receptors and epidermal growth factor receptor is a redundant pathway that participates in multiple pathophysiological processes. Specific and detailed knowledge of purinergic receptor-regulated pathways advances our understanding of the complexity of GPCR signal transduction and opens the way for pharmacologic intervention in the pathological context.

Exploring the mechanism of action of total glucosides of paeony against autoimmune thyroiditis based on network pharmacology and molecular docking

The objective of this study is to explore the potential mechanism of action of Total glucosides of paeony (TGP) in the treatment of autoimmune thyroiditis (AIT). The study utilized literature mining to obtain the active ingredients of TGP. Databases such as Super-PRED, similarity ensemble approach, and Swiss Target Prediction were utilized to predict the targets of the active ingredients. DisGeNET, Dangbank, GeneCards, online mendelian inheritance in man, and Pharmgkb databases were used to obtain the targets related to AIT. The Venn Online tool was used to screen the intersecting genes between the active ingredients and AIT targets. The STRING database was employed to analyze protein protein interaction. Gene ontology bio-enrichment and Kyoto encyclopedia of genes and genomes enrichment of common targets were analyzed using R language. Finally, molecular docking was performed using AutoDockTools-1.5.6 software for validation. The study identified 5 active ingredients of TGP, 283 ingredient targets, 7120 disease targets, 220 intersecting targets, 30 entries for gene ontology analysis, and 30 pathways for Kyoto encyclopedia of genes and genomes analysis. The important targets of the protein protein interaction network were identified as interleukin-6, proto-oncogene tyrosine-protein kinase, epidermal growth factor receptor, among others. The molecular docking validation results showed that Paeoniflorin, albiflorin, and benzoylpaeoniflorin and oxypaeoniflor all bind well to interleukin-6, epidermal growth factor receptor, and proto-oncogene tyrosine-protein kinase. This study reveals the multi-component, multi-target and multi-pathway mechanism of action of TGP in regulating AIT and provides a reference for subsequent basic research.

Paeoniflorin protects 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease mice by inhibiting oxidative stress and neuronal apoptosis through activating the Nrf2/HO-1 signaling pathway

OBJECTIVES

This study aimed to explore the neuroprotective effects of paeoniflorin on oxidative stress and apoptosis in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mice.

METHODS

The effects of paeoniflorin on motor function in mice were evaluated by behavioral test. Then substantia nigra of mice were collected and neuronal damage was assessed using Nissl staining. Positive expression of tyrosine hydroxylase (TH) was detected by immunohistochemistry. Levels of malondialdehyde, superoxide dismutase (SOD) and glutathione were measured by biochemical method. terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay was used to detect apoptosis of dopaminergic neurons. Western blotting and real-time fluorescence quantitative PCR were used to detect the protein and mRNA expressions of Nrf2, heme oxygenase-1 (HO-1), B-cell lymphoma-2(Bcl-2), Bax and cleaved caspase-3.

RESULTS

Paeoniflorin treatment significantly ameliorated the motor performance impairment in MPTP-induced PD mice. Moreover, it notably increased the positive expression rate of TH and reduced the damage and apoptosis of dopaminergic neurons in the substantia nigra. Furthermore, paeoniflorin increased the levels of SOD and glutathione and decreased the malondialdehyde content. It also promoted Nrf2 nuclear translocation, increased the protein and mRNA expressions of HO-1 and Bcl-2 and reduced the protein and mRNA expressions of BCL2-Associated X2 (Bax) and cleaved caspase-3. Treatment with the Nrf2 inhibitor, ML385, notably reduced the effects of paeoniflorin in MPTP-induced PD mice.

CONCLUSIONS

Neuroprotective effects of paeoniflorin in MPTP-induced PD mice may be mediated via inhibition of oxidative stress and apoptosis of dopaminergic neurons in substantia nigra through activation of the Nrf2/HO-1 signaling pathway.

Modulatory Efficiency of LP/LF Nano-Combination on Neurochemical and Behavioural Retardations in the Brain of Induced-Epileptic Rats

&lt;b&gt;Background and Objective:&lt;/b&gt; Epilepsy is one of the normal neurological problems that came about because of strange electrical movements and prompt serious and far-reaching cell misfortune in the mind. This study aimed to investigate if a nano-Chitosan formulation loaded with bovine milk lactoperoxidase (LPO) and lactoferrin (LF) could prevent Lithium Chloride/Pilocarpine-induced epilepsy in rats or not. &lt;b&gt;Materials and Methods:&lt;/b&gt; Adult male rats (200-250 g) were partitioned into four groups (8 animals each) as follows: Group (1) Normal rats served as control group and received saline orally, group (2) Normal rats ingested with a daily oral dose of LPO and LF-NPS formulation at 50 mg kg&lt;sup&gt;&lt;/sup&gt;&lt;sup&gt;1&lt;/sup&gt;, group (3) Pilocarpine-induced epileptic rats and group (4) Epilepsy-modeled rats were treated with LPO+LF NPs (50 mg/kg/day, orally) for 6 weeks. &lt;b&gt;Results:&lt;/b&gt; The results revealed that the administration of LPO+LF-NPs markedly improved the induced-epilepsy disorders, this was monitored from the significant reduction in the values of caspase-3, TNF-α, IL-1β, CD4&lt;sup&gt;+&lt;/sup&gt;, MDA and NO coupled with remarkable raise in AchE-ase, dopamine, serotonin, SOD and GPx, CAT and GSH values in both brain regions. &lt;b&gt;Conclusion:&lt;/b&gt; This study supported the anti-epilepsy features of LPO+LF-NPS against Lithium Chloride/Pilocarpine-induced epilepsy in rats through the improvement of the immune response, reduction of inflammation and restoration of the impaired oxidative stress status.

Efficacy and safety of LongShengZhi capsule on functional recovery after acute ischemic stroke (LONGAN): Protocol and statistical analysis plan for a randomized, double-blind, placebo-controlled trial

Background: Due to limited time windows and technical requirements, only a small percentage of patients can receive reperfusion therapy for acute ischemic stroke (AIS). Previous studies have shown that LongShengZhi (LSZ) capsule can improve neurological outcomes in patients after AIS, yet those results have not been finally verified through rigorous randomized controlled trials. Thus, this trial was designed to further clarify the efficacy and safety of LSZ capsule for patients with AIS. Methods: LSZ capsule on Functional Recovery after Acute Ischemic Stroke (LONGAN) trial is a prospective, multicenter, randomized, placebo-controlled, double-blind, parallel-group, superiority trial that enrolls patients from stroke and rehabilitation units in China. We will enroll 1,376 patients aged 18 years or older with AIS within 7 days of symptom onset and a National Institute of Health Stroke Scale (NIHSS) score of 4-15. Eligible patients will be randomized to receive either 2 g LSZ capsules three times a day or placebo LSZ capsules for 90 days. The primary outcome is the proportion of patients with favorable outcomes, as measured by the modified Rankin Scale (mRS) 90 days after randomization. The main safety outcome is the proportion of severe adverse events. Conclusion: This study will be the first randomized, double-blind trial to evaluate the efficacy and safety of LSZ capsule in patients with AIS. In order to improve the transparency and reproducibility of the trial, the data will be analyzed in accordance with this pre-specified plan for statistical analysis to reduce bias due to selective analysis and reporting. This trial aims to provide high-quality evidence for the efficacy and safety of LSZ capsule for AIS.

The Neuroprotective Effects of Paeoniflorin Against MPP+-induced Damage to Dopaminergic Neurons via the Akt/Nrf2/GPX4 Pathway

Paeoniflorin (PF), a water-soluble monoterpene glycoside extracted from the root of Paeonia lactiflora Pall, has been shown to exert neuroprotective effects against neurodegenerative diseases such as Parkinson's disease (PD). However, its underlying mechanisms remain unknown. Our results showed that at certain concentrations, PF alleviated 1-methyl-4-phenylpyridinium (MPP⁺)-induced morphological damage and inhibited neuronal ferroptosis. Moreover, our research indicated that the neuroprotective effect of PF could be partially blocked by ML385 (a nuclear factor erythroid-2-related factor 2 (Nrf2) inhibitor) and LY29400 (an Akt inhibitor). These findings suggest that PF protects against MPP⁺-induced neurotoxicity by preventing ferroptosis via activation of the Akt/Nrf2/Gpx4 pathway in vitro.

Beneficial effects of mijianchangpu decoction on ischemic stroke through components accessing to the brain based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

To explore the effective components, potential targets and neuroprotective related mechanisms of Mijianchangpu decoction (MJCPD), a well-known TCM used by the Chinese Hui minorities to treat stroke, on the prevention and treatment of ischemic stroke (IS) by using experimental models combined with network pharmacology.

MATERIALS AND METHODS

The neuroprotective efficacy of MJCPD was estimated by applying the middle cerebral artery occlusion (MCAO) induced cerebral ischemia rats, and the neurological deficits score, TTC and HE staining as well as behavioral evaluation tests were employed to evaluate the beneficial effects. Meanwhile, the bioactive components of MJCPD responsible for the neuroprotective effects were identified by detecting the constituents in the brain of the MCAO rats with UHPLC-QTOF-MS/MS techniques, and these compounds were then underwent for network pharmacology analysis. Firstly, the targets of the bioactive compounds of MJCPD were predicted using Pharmmapper database, and simultaneously, the targets of IS disease were obtained from disease databases including DisGenet, OMIM, and GeneCards. Secondly, the protein-protein interaction (PPI) network between the targets and diseases were established to give the possible therapeutic targets for IS. Thirdly, the go function and KEGG pathway enrichment analysis were carried out and the compound-target-pathway network was constructed by Cytoscape software. Finally, the effective compounds, core targets and possible pathways were obtained by analyzing the connectivity of the network. More importantly, the core targets were verified by western blot experiments to validate the reliability of this study.

RESULTS

MJCPD exhibited significant neuroprotective effect on IS, and 16 bioactive components of MJCPD were identified in the brain of the MCAO rats. 59 and 1982 targets related with IS disease were explored from Pharmapper and disease databases, respectively, and 32 intersecting targets were obtained as hypothetical therapeutic targets. Based on the results of the compound-target-pathway and PPI network with the degree was greater than the median, 8 effective compounds (suberic acid, epishyobunone, crocetin monomethyl ester, sfaranal, (Z)-6-octadccenoic acid, nerolidol and gurjunene) and 5 hub targets (SRC, MAPK8, MAPK14, EGFR and MAPK1) as well as 12 pathways were predicted. Western blot results showed that EGFR, p38, ERK and SRC proteins were expressed significantly different after MJCPD treatment as compared with the model group.

CONCLUSION

The present study employed network pharmacology, pharmacodynamics and molecular biology techniques to predict and validate the core potential targets and signaling pathways as well as the bioactive components of MJCPD responsible for the treatment of IS. All of which are very helpful to clarify the neuroprotective mechanism of MJCPD, and obviously, the active compounds and targets in this study can also provide clues for the treatment of IS.

Paeoniflorin ameliorates ischemic injury in rat brain via inhibiting cytochrome c/caspase3/HDAC4 pathway

Paeoniflorin (PF), a bioactive monoterpene glucoside, has shown a variety of pharmacological effects such as anti-inflammation and autophagy modulation etc. In this study, we investigated whether and how PF exerted a protective effect against ischemic brain injury in vivo and in vitro. Primary rat cortical neurons underwent oxygen/glucose deprivation/reperfusion (OGD/R) for 90 min. We showed that after OGD/R, a short fragment of histone deacetylase 4 (HDAC4) produced by caspase3-mediated degradation was markedly accumulated in the nucleus and the activity of caspase3 was increased. Treatment with PF (100 nM, 1 μM) significantly improved the viability of cortical neurons after OGD/R. Furthermore, PF treatment could maintain HDAC4 intrinsic subcellular localization and reduce the caspase3 activity without changing the HDAC4 at the transcriptional level. PF treatment significantly reduced OGD/R-caused inhibition of transcriptional factor MEF2 expression and increased the expression of downstream proteins such as GDNF, BDNF, and Bcl-xl, thus exerting a great anti-apoptosis effect as revealed by TUNEL staining. The beneficial effects of PF were almost canceled in HDAC4 (D289E)-transfected PC12 cells after OGD/R. In addition, PF treatment reduced the caspase9 activity, rescued the release of cytochrome c from mitochondria, and maintained the integrity of mitochondria membrane. We conducted in vivo experiments in 90-min-middle cerebral artery occlusion (MCAO) rat model. The rats were administered PF (20, 40 mg/kg, ip, 3 times at the reperfusion, 24 h and 48 h after the surgery). We showed that PF administration dose-dependently reduced infarction area, improved neurological symptoms, and maintained HDAC4 localization in rats after MCAO. These results demonstrate that PF is effective in protecting against ischemic brain injury and inhibit apoptosis through inhibiting the cytochrome c/caspase3/HDAC4 pathway.

Paeoniflorin: A neuroprotective monoterpenoid glycoside with promising anti-depressive properties

BACKGROUND

Depression, as a prevalent and debilitating psychiatric disease, severely decreases the life quality of individuals and brings heavy burdens to the whole society. Currently, some antidepressants are applied in the treatment of severe depressive symptoms, while there are still some undesirable drawbacks. Paeoniflorin is a monoterpenoid glycoside that was firstly extracted from Paeonia lactiflora Pall, a traditional Chinese herb that is widely used in the Chinese herbal formulas for treating depression.

PURPOSE

This review summarized the previous pre-clinical studies of paeoniflorin in treating depression and further discussed the potential anti-depressive mechanisms for that paeoniflorin to be further explored and utilized in the treatment of depression clinically.

METHODS

Some electronic databases, e.g., PubMed and China National Knowledge Infrastructure, were searched from inception until April 2021.

RESULTS

This review summarized the effective anti-depressive properties of paeoniflorin, which is related to its functions in the upregulation of the levels of monoaminergic neurotransmitters, inhibition of the hypothalamic-pituitary-adrenal axis hyperfunction, promotion of neuroprotection, promotion of hippocampus neurogenesis, and upregulation of brain-derived neurotrophic factor level, inhibition of inflammatory reaction, downregulation of nitric oxide level, etc. CONCLUSION: This review focused on the pre-clinical studies of paeoniflorin in depression and summarized the recent development of the anti-depressive mechanisms of paeoniflorin, which approves the role of paeoniflorin plays in anti-depression. However, more high-quality pre-clinical and clinical studies are expected to be conducted in the future.

Activation of Adenosine A1 Receptor in Ischemic Stroke: Neuroprotection by Tetrahydroxy Stilbene Glycoside as an Agonist

Ischemic stroke is the main cause of death/disability, posing a great menace to human health. Though efforts to search for therapeutic drugs are ongoing, few of them have succeeded. Adenosine A₁ receptor (A1R) activation could ameliorate ischemic injury, representing a very tempting target for stroke treatment. Tetrahydroxy stilbene glycoside (TSG), a potent antioxidant from the well-known Chinese herb Polygonum multiflorum Thunb., has been reported to have notable neuroprotective activities but the underlying mechanisms are elusive. This study investigated the mechanism of TSG focusing on A1R. TSG markedly decreased mortality, neurological deficit score, cerebral infarct size and brain water content of MCAO rats, and ameliorated the disorders in purine metabolism, energy metabolism and antioxidative defense system. TSG helped the survival of SH-SY5Y cells in OGD/R by alleviating oxidative stress and glutamate release, and by maintaining calcium homeostasis. TSG effects were abolished by A1R antagonist DPCPX. Docking and binding assays confirmed the binding of TSG with A1R. In addition, TSG upregulated the A1R level lowered by MCAO and OGD/R. The downstream signals of A1R activation, ERK1/2, HIF-1α and NF-κB contributed to the neuroprotection of TSG. Moreover, void of “well-known” cardiovascular side effects of classical A1R agonists, TSG showcased its great potential for stroke treatment.

Caffeine and Its Neuroprotective Role in Ischemic Events: A Mechanism Dependent on Adenosine Receptors

Ischemia is characterized by a transient, insufficient, or permanent interruption of blood flow to a tissue, which leads to an inadequate glucose and oxygen supply. The nervous tissue is highly active, and it closely depends on glucose and oxygen to satisfy its metabolic demand. Therefore, ischemic conditions promote cell death and lead to a secondary wave of cell damage that progressively spreads to the neighborhood areas, called penumbra. Brain ischemia is one of the main causes of deaths and summed with retinal ischemia comprises one of the principal reasons of disability. Although several studies have been performed to investigate the mechanisms of damage to find protective/preventive interventions, an effective treatment does not exist yet. Adenosine is a well-described neuromodulator in the central nervous system (CNS), and acts through four subtypes of G-protein-coupled receptors. Adenosine receptors, especially A₁ and A_2A receptors, are the main targets of caffeine in daily consumption doses. Accordingly, caffeine has been greatly studied in the context of CNS pathologies. In fact, adenosine system, as well as caffeine, is involved in neuroprotection effects in different pathological situations. Therefore, the present review focuses on the role of adenosine/caffeine in CNS, brain and retina, ischemic events.

LongShengZhi Capsule Attenuates Alzheimer-Like Pathology in APP/PS1 Double Transgenic Mice by Reducing Neuronal Oxidative Stress and Inflammation

Alzheimer’s disease (AD) is the most common form of dementia in the elderly. It may be caused by oxidative stress, inflammation, and cerebrovascular dysfunctions in the brain. LongShengZhi Capsule (LSZ), a traditional Chinese medicine, has been approved by the China Food and Drug Administration for treatment of patients with cardiovascular/cerebrovascular disease. LSZ contains several neuroprotective ingredients, including Hirudo, Astmgali Radix, Carthami Flos (Honghua), Persicae Semen (Taoren), Acori Tatarinowii Rhizoma (Shichangpu), and Acanthopanax Senticosus (Ciwujia). In this study, we aimed to determine the effect of LSZ on the AD process. Double transgenic mice expressing the amyloid-β precursor protein and mutant human presenilin 1 (APP/PS1) to model AD were treated with LSZ for 7 months starting at 2 months of age. LSZ significantly improved the cognition of the mice without adverse effects, indicating its high degree of safety and efficacy after a long-term treatment. LSZ reduced AD biomarker Aβ plaque accumulation by inhibiting β-secretase and γ-secretase gene expression. LSZ also reduced p-Tau expression, cell death, and inflammation in the brain. Consistently, in vitro, LSZ ethanol extract enhanced neuronal viability by reducing L-glutamic acid-induced oxidative stress and inflammation in HT-22 cells. LSZ exerted antioxidative effects by enhancing superoxide dismutase and glutathione peroxidase expression, reduced Aβ accumulation by inhibiting β-secretase and γ-secretase mRNA expression, and decreased p-Tau level by inhibiting NF-κB-mediated inflammation. It also demonstrated neuroprotective effects by regulating the Fas cell surface death receptor/B-cell lymphoma 2/p53 pathway. Taken together, our study demonstrates the antioxidative stress, anti-inflammatory, and neuroprotective effects of LSZ in the AD-like pathological process and suggests it could be a potential medicine for AD treatment.

In Vitro Evaluation of the Neuroprotective Effect of Panax notoginseng Saponins by Activating the EGFR/PI3K/AKT Pathway

OBJECTIVE

This study investigated whether Panax notoginseng saponins (PNS) extracted from Panax notoginseng (Bruk.) F. H. Chen played a neuroprotective role by affecting the EGFR/PI3K/AKT pathway in oxygen-glucose deprived (OGD) SH-SY5Y cells.

MATERIALS AND METHODS

Different groups of OGD SH-SY5Y cells were treated with varying doses of PNS, PNS + AG1478 (a specific inhibitor of EGFR), or AG1478 for 16 hours. CCK8, Annexin V-FITC/PI apoptosis analysis, and LDH release analysis were used to determine cell viability, apoptosis rate, and amounts of LDH. Quantitative real-time PCR (q-RT-PCR) and western blotting were used to measure mRNA and proteins levels of p-EGFR/EGFR, p-PI3K/PI3K, and p-AKT/AKT in SH-SY5Y cells subjected to OGD.

RESULTS

PNS significantly enhanced cell viability, reduced apoptosis, and weakened cytotoxicity by inhibiting the release of LDH. The mRNA expression profiles of EGFR, PI3K, and AKT showed no difference between model and other groups. Additionally, ratios of p-EGFR, p-PI3K, and p-AKT to EGFR, PI3K, and AKT proteins expression, respectively, all increased significantly.

CONCLUSIONS

These findings indicate that PNS enhanced neuroprotective effects by activating the EGFR/PI3K/AKT pathway and elevating phosphorylation levels in OGD SH-SY5Y cells.

Paeoniflorin inhibits tributyltin chloride-induced apoptosis in hypothalamic neurons via inhibition of MKK4-JNK signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Paeoniflorin (PF) exerts a significant protective effect against neurotoxicity and mitochondrial damage in neurons. However, the mechanisms underlying PF-mediated rescue remain elusive. Therefore, we endeavored to further research the molecular mechanisms underlying PF-mediated inhibition of tributyltin chloride (TBTC)-induced apoptosis of neurons.

AIM OF THE STUDY

To investigate the influence and possible mechanism of action of PF in TBTC-induced neurodegenerative disease.

MATERIALS AND METHODS

First, primary hypothalamic neurons were treated with tributyltin chloride (150 μg/L) and PF (25, 50, and 100 μM). 17β-estradiol (1 nM) was used as a positive control. Subsequently, CCK-8 assay was performed. The level of apoptosis was examined by flow cytometry and the function of mitochondria was reflected by MMP levels. The mRNA expression levels of B-cell lymphoma-2 (Bcl-2), together with Bax, were examined using qRT-PCR. The protein levels of mitogen-activated protein kinase kinase 4 (MKK4), c-Jun N-terminal kinase (JNK), Bcl-2, Bax, and Caspase-3 were examined using western blotting. Finally, pretreatment with JNK agonist, anisomycin, was done to observe the change in expressions of MKK4 and JNK.

RESULTS

Paeoniflorin treatment reduced TBTC-induced damage and neuron loss in a dose-dependent manner. Decrease in mitogen-activated protein kinase (MAPK) as well as JNK levels were reversed by treatment with paeoniflorin via inhibition of JNK activation. Furthermore, ratio of levels of Bcl-2/Bax increased while the activation of caspase-3 was suppressed. In addition, pretreatment with JNK agonist, anisomycin effectively suppressed TBTC-induced cytotoxicity in hypothalamic neuron.

CONCLUSIONS

PF can potentially be used to prevent and/or treat neurodegenerative diseases and neural injury by inhibiting MKK4-JNK signaling pathway.

Reversal of Multidrug Resistance in Human Colon Cancer and Human Leukemia Cells by Three Plant Extracts and Their Major Secondary Metabolites

Background: We studied the effect of three plant extracts (Glycyrrhiza glabra, Paeonia lactiflora, Eriobotrya japonica) and six of their major secondary metabolites (glycyrrhizic acid, 18β glycyrrhetinic acid, liquiritigenin, isoliquiritigenin, paeoniflorin, ursolic acid) on the multidrug resistant human colon cancer cell line Caco-2 and human leukemia cell line CEM/ADR 5000 as compared to the corresponding sensitive cell line CCRF-CEM, and human colon cancer cells HCT-116, which do not over-express ATP-binding cassette (ABC) transporters. Methods: The cytotoxicity of single substances in sensitive and resistant cells was investigated by MTT assay. We also applied combinations of extracts or single compounds with the chemotherapeutic agent doxorubicin or doxorubicin plus the saponin digitonin. The intracellular retention of the ABC transporter substrates rhodamine 123 and calcein was examined by flow cytometry to explore the effect of the substances on the activity of ABC transporters P-glycoprotein and MRP1. Real-time PCR was applied to analyse the gene expression changes of ABCB1, ABCC1, caspase 3, caspase 8, AhR, CYP1A1, and GSTP1 in resistant cells under the treatment of the substances. Results: All the substances moderately inhibited cell growth in sensitive and resistant cells to some degree. Whereas ursolic acid showed IC50 of 14 and 22 µM in CEM/ADR 5000 and Caco-2 cells, respectively, glycyrrhizic acid and paeoniflorin were inactive with IC50 values above 400 μM. Except for liquiritigenin and isoliquiritigenin, all the other substances reversed MDR in CEM/ADR 5000 and Caco-2 cells to doxorubicin. Ue, ga, 18ga, and urs were powerful reversal agents. In CEM/ADR 5000 cells, high concentrations of all the substances, except Paeonia lactiflora extract, increased calcein or rhodamine 123 retention in a dose-dependent manner. In Caco-2 cells, all the substances, except liquiritigenin, retained rhodamine 123 in a dose-dependent manner. We also examined the effect of the plant secondary metabolite (PSM) panel on the expression of ABCB1, ABCC1, caspase 3, caspase 8, AhR, CYP1A1, and GSTP1 genes in MDR cells. Conclusions: The extracts and individual PSM could reverse MDR in CEM/ADR 5000 and Caco-2 cells, which overexpress ABC transporters, in two- and three-drug combinations. Most of the PSM also inhibited the activity of ABC transporters to some degree, albeit at high concentrations. Ue, ga, 18ga, and urs were identified as potential multidrug resistance (MDR) modulator candidates, which need to be characterized and validated in further studies.

The role of adenosine in up-regulation of p38 MAPK and ERK during limb ischemic preconditioning-induced brain ischemic tolerance

Our previous studies have demonstrated that limb ischemic preconditioning (LIP) induced brain ischemic tolerance and up-regulated the expression of p38 MAPK and ERK in the hippocampal CA1 region in rats. The present study was undertaken to investigate the role of adenosine in brain protection and up-regulation of p38 MAPK and ERK induced by LIP. It was found that adenosine A1 receptor antagonist DPCPX dose-dependently inhibited the protective effect of LIP. The up-regulation of p38 MAPK and ERK induced by LIP could be blocked by DPCPX. Furthermore, we observed the effect of adenosine on the brain ischemia. The results showed that pre-administration of adenosine could partly mimic the neuroprotective effect on the brain, up-regulate the expression of p38 MAPK and ERK. Based on the above results, it can be concluded that adenosine participated in brain protection and up-regulation of the expression of p38 MAPK and ERK during the induction of brain ischemic tolerance after LIP.

Cytoprotective effects of paeoniflorin are associated with translocator protein 18 kDa

Paeoniflorin (PF) is one of the important active components in peony that are known to produce the neuroprotective effects. However, the involved cytoprotective factors on brain astrocytes are remain unclear. Translocator protein 18 kDa (TSPO) and its downstream neurosteroids biosynthesis play a significant role in cytoprotection. Based on these, the role of TSPO and neurosteroids biosynthesis in the cytoprotective effects of PF is evaluated. The astrocyte cells were cultured and AC-5216 (TSPO ligand) was selected as the positive control drug. The cytoprotective effects of PF and the levels of neurosteroids were quantified by water-soluble tetrazolium assay and enzyme linked immunosorbent assay, respectively. The cytoprotective activities of PF were relevant to neurosteroids (e.g. progsterone and allopregnanolone) biosynthesis, while these effects were totally blocked by PK11195, trilostane and finasteride, respectively. In summary, the cytoprotective effects of PF maybe mediated by TSPO and neurosteroids biosynthesis. The findings may provide the new insights into the cytoprotective effects of PF.

Optimizing Hydrophobic Groups in Amphiphiles to Induce Gold Nanoparticle Complex Vesicles for Stability Regulation

Polymeric graft polyphosphazene containing 4-aminobenzoic acid diethylaminoethyl ester (DEAAB) as hydrophobic side groups was rationally designed and named PDEP. PDEP can self-assemble into a nanovesicle in water. More importantly, when compared with the amphiphile poly[(methoxy-poly(ethylene glycol))(ethyl p-aminobenzoate)]phosphazene (PEP) copolymer containing benzene rings and the amphiphile poly[(methoxy-poly(ethylene glycol)(N,N-diisopropylethylenediamine)]phosphazene (PDP) copolymer containing tertiary amino groups, the coexistence of benzene and tertiary amino groups in PDEP enabled it to effectively load water-soluble small-molecule doxorubicin hydrochloride (DOX·HCl) into the vesicle and efficiently induce in situ transformation of gold tetrachloroaurate (HAuCl₄) to gold nanoparticles (AuNPs) as both a reductant and a stabilizer. By optimizing the reduction conditions, such as the temperature, reaction time, and hydrophobic group in polymer/HAuCl₄ molar ratio, the AuNP complex PDEP vesicles significantly inhibited the DOX·HCl burst release at pH 7.4 while displaying a fast release responsive to pH 5.5.

JAK2/STAT3 pathway is involved in the protective effects of epidermal growth factor receptor activation against cerebral ischemia/reperfusion injury in rats

Cerebral ischemia and reperfusion is a common pathophysiologic process, which is involved in stroke and brain trauma. Recent studies revealed that activating epidermal growth factor receptor (EGFR) ameliorates cerebral ischemia/reperfusion (I/R) injury, however, the precise mechanisms remain to be illuminated. In this study, the neurological behavior was evaluated by Longa score. The infarct volume was performed by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining and the expression of p-EGFR, p-STAT3, connexin (Cx43), Bax and Bcl-2 were detected by Western blot. The neurological behavior and infarct volume were increased in rats with cerebral I/R injury. Epidermal growth factor (EGF) pretreatment significantly decreased neurological deficit and infarct volume. However, the antagonist of EGFR, AG1478 attenuated the EGF-induced reduction of neurological deficit and infarct volume. Moreover, the inhibitor of JAK2/STAT3, AG490 undermined the protective effects stimulated by activating EGFR in rats with I/R injury. In addition, EGF pretreatment increased the expression of Bcl-2 and reduced the expression of Bax and Cx43, and the effects were abolished after using AG1478 and AG490. These findings implicate that JAK2/STAT3 pathway plays the vital role in I/R injury protection from activating EGFR. And the neuroprotective effects may associate with inhibiting the Cx43 expression and the inhibition of apoptosis.

Protective effects of paeoniflorin and albiflorin on chemotherapy-induced myelosuppression in mice

Paeonia lactiflora root (baishao in Chinese) is a commonly used herb in traditional Chinese medicines (TCM). Two isomers, paeoniflorin (PF) and albiflorin (AF), are isolated from P. lactiflora. The present study aimed to investigate the protective effects of PF and AF on myelosuppression induced by chemotherapy in mice and to explore the underlying mechanisms. The mouse myelosuppression model was established by intraperitoneal (i.p.) injection of cyclophosphamide (CP, 200 mg·kg(-1)). The blood cell counts were performed. The thymus index and spleen index were also determined and bone morrow histological examination was performed. The levels of tumor necrosis factor-α (TNF-α) in serum and colony-stimulating factor (G-CSF) in plasma were measured by Enzyme-Linked Immunosorbent Assays (ELISA) and the serum levels of interleukin-3 (IL-3), granulocyte-macrophagecolony-stimulatingfactor (GM-CSF), and interleukin-6 (IL-6) were measured by radioimmunoassay (RIA). The levels of mRNA expression protein of IL-3, GM-CSF and G-CSF in spleen and bone marrow cells were determined respectively. PF and AF significantly increased the white blood cell (WBC) counts and reversed the atrophy of thymus. They also increased the serum levels of GM-CSF and IL-3 and the plasma level of G-CSF and reduced the level of TNF-α in serum. PF enhanced the mRNA level of IL-3 and AF enhanced the mRNA levels of GM-CSF and G-CSF in the spleen. PF and AF both increased the protein levels of GM-CSF and G-CSF in bone marrow cells. In conclusion, our results demonstrated that PF and AF promoted the recovery of bone marrow hemopoietic function in the mouse myelosuppression model.

Hematopoietic Effects of Paeoniflorin and Albiflorin on Radiotherapy-Induced Myelosuppression Mice

Paeonia lactiflora root (baishao in Chinese) is a commonly used herb in traditional Chinese medicine (TCM). Paeoniflorin (PF) and albiflorin (AF) are two major active constituents of P. lactiflora. In this paper, we aimed to investigate the hematopoietic effects of PF and AF on myelosuppression mice induced by radiotherapy and to explore the underlying mechanism. The finding indicated that PF and AF significantly increased the numbers of white blood cells (WBC) and reversed the atrophy of thymus. Furthermore, PF and AF increased the levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) and reduced the levels of tumor necrosis factor-α (TNF-α) in serum and increased the level of colony-stimulating factor (G-CSF) in plasma. Lastly, PF and AF not only enhanced the mRNA levels of GM-CSF and G-CSF in the spleens, but also increased the protein levels of G-CSF and GM-CSF in bone marrow. Our results suggest that PF and AF may promote the recovery of bone marrow hemopoietic function in a myelosuppressed mouse model.

Total glucosides of peony attenuates experimental autoimmune encephalomyelitis in C57BL/6 mice

Total glucosides of peony (TGP), an active compound extracted from the roots of Paeonia lactiflora Pall, has wide pharmacological effects on nervous system. Here we examined the effects of TGP on experimental autoimmune encephalomyelitis (EAE), an established model of multiple sclerosis (MS). The results showed that TGP can reduce the severity and progression of EAE in C57 BL/6 mice. In addition, TGP also down-regulated the Th1/Th17 inflammatory response and prevented the reduced expression of brain-derived neurotrophic factor and 2',3'-cyclic nucleotide 3'-phosphodiesterase of EAE. These findings suggest that TGP could be a potential therapeutic agent for MS.